Mystery Solved?

A new culprit is found in the collapse of beehives

Jan 06, 2012 | By Joe Levit

LINDA DAVIDSON—THE WASHINGTON POST/GETTY IMAGES

Honeybee colonies across the country have been dying off at high rates in recent years. Scientists have been working on the problem, but have not found a solution. Until recently, they have been looking at factors such as pesticides, fungi and viruses to explain the honeybee die-off. Now, researchers at San Francisco State University have found a new possible cause of the problem—a parasitic fly.

A Pesky Fly

The fly, called a phorid fly, has been known as a bumblebee parasite. But scientists have found out by accident that the fly may also be bothering honeybees.

Three years ago, the study’s lead researcher, John Hafernik, was trying to find something to feed to a praying mantis. The biology professor caught some honeybees outside his classroom and put them in a container. But he forgot to feed them to the praying mantis. When he found the container a week later, the bees inside were dead. All around them were small fly pupae. These pupae eventually turn into phorid flies.

CHRISTOPHER QUOCK—SAN FRANCISCO STATE UNIVERSITY/AP

A phorid fly stands on the back of this honeybee. It deposits eggs into the bee's abdomen. The eggs will hatch and the bee will then die.

"The parasite could be another stressor, enough to push the bee over a tipping point. Or it could play a primary role in causing the disease,” said Hafernik.

A fly will latch onto a honeybee, and then deposit eggs into the bee’s abdomen. As the fly larvae, or worms, grow inside the bee, the bee starts to lose control of its thought and motion. It will begin to walk around in circles or fly blindly toward a light source. Then the bee soon dies. If this process happens to lots of bees at once, it becomes a big problem.

Colony Collapse Disorder

When all the adult honeybees in a colony suddenly disappear, it is called colony collapse disorder. Scientists first recognized the disorder in 2006. Since then, 30%of bee colonies have been lost per year.

This is a problem for everyone. Bees help us grow the food we eat. They fly from flower to flower, pollinating about a third of the food supply in the United States. In California—the nation’s top producer of fruits and vegetables—colony collapse disorder is affecting the $2 billion almond industry, as well as many other crops. Hopefully scientists can find out how to help honeybees soon. We’d bee in trouble without them!